Recovery of Damaged Solid Propellants by Interrupting Burning and Crack-Propagaton Processes PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Recovery of Damaged Solid Propellants by Interrupting Burning and Crack-Propagaton Processes PDF full book. Access full book title Recovery of Damaged Solid Propellants by Interrupting Burning and Crack-Propagaton Processes by J. Mantzaras. Download full books in PDF and EPUB format.
Author: J. Mantzaras
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
Get Book Here
Book Description
Crack propagation in burning solid propellants and explosives can affect the performance of a rocket motor by increasing both the burning surface area and local pressurization rates. This may sometimes lead to deflagration-to-detonation transition (DDT) or detonation due to some unresolved mechanisms (XDT). In order to obtain direct evidence of structural damage of the propellant sample during crack propagation and branching, an interrupted burning experiment has been designed, constructed, and tested. Sample recovered from a preliminary test firing showed rough surface structure and several macrocracks in directions from the initial crack orientation. The propellant sample is believed to undergo significant cracking and branching before the extinction. This is supported by the experimental evidence of rough and cracked surfaces of the recovered sample, source-flow pattern observed from high-speed movie films, and extremely rapid pressurization of the source-flow region beyond the initial crack tip due to the fast burning of damaged propellant sample. (Author).
Author: J. Mantzaras
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
Get Book Here
Book Description
Crack propagation in burning solid propellants and explosives can affect the performance of a rocket motor by increasing both the burning surface area and local pressurization rates. This may sometimes lead to deflagration-to-detonation transition (DDT) or detonation due to some unresolved mechanisms (XDT). In order to obtain direct evidence of structural damage of the propellant sample during crack propagation and branching, an interrupted burning experiment has been designed, constructed, and tested. Sample recovered from a preliminary test firing showed rough surface structure and several macrocracks in directions from the initial crack orientation. The propellant sample is believed to undergo significant cracking and branching before the extinction. This is supported by the experimental evidence of rough and cracked surfaces of the recovered sample, source-flow pattern observed from high-speed movie films, and extremely rapid pressurization of the source-flow region beyond the initial crack tip due to the fast burning of damaged propellant sample. (Author).
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 968
Get Book Here
Book Description
Author: Kenneth K. Kuo
Publisher:
ISBN:
Category :
Languages : en
Pages : 116
Get Book Here
Book Description
Three major tasks performed during the report period of investigation were: i) crack propagation and branching in burning solid propellants, ii) ignition of nitramine-based composite propellants under rapid pressurization, and iii) ignition of nitramine-based composite propellants by CO2 laser. Propellant samples have been recovered by interrupted burning experiments. Four modes of crack propagation and/or branching were observed. The amount of surface area generated by mixed or branched modes is substantially higher than that of the single crack propagation mode, and thus could cause sufficiently severe burning in the damaged zone to result in rocket motor failure. The crack propagation problem is analyzed through the use of basic physical principles, experimental results, and Schaper's theory of crack propagation. A set of governing dimensionless parameters which control and characterize the degree of damage has been obtained. These parameters can be used to develop guidelines for safe operating conditions of rocket motors. Ignition characteristics of a series of RDX-based composite propellants were studied. The times for the onset of light emission (t sub LE) of different propellants under rapid pressurization were compared. It is also found that propellant samples with shorter t sub LE do not necessarily show higher mass consumption, this indicates that propellant vulnerabilty should be evaluated by both t sub LE and the fraction of mass consumed.
Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 474
Get Book Here
Book Description
Author: Yeu-Cherng Lu
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Jeffrey A. Nimis
Publisher:
ISBN:
Category :
Languages : en
Pages : 70
Get Book Here
Book Description
The importance of crack propagation in solid rocket motors is widely recognized. However, the processes of crack propagation and branching in burning solid propellants are not as yet well understood. These processes could be instrumental in creating large specific surface areas for burning causing rocket motor failure. Key factors influencing the crack combustion, propagation and branching process considered in the dimensional analysis include chamber pressurization rate, initial crack length, initial temperature, sample geometry, and mechanical and thermal properties of the solid propellant. (jes).
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 1244
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 196
Get Book Here
Book Description
Two major tasks performed during the report period of investigation were: (i) laser ignition of nitramine-based composite propellants using a high- powered CO2 laser in (ii) crack propagation and branching in burning solid propellants. The laser ignition of a series of RDX-based composite propellants was studied theoretically and experimentally. A comprehensive model for the radiative ignition of the nitramine composite propellants was formulated. The theoretical model was solved numerically. A radiative ignition test setup employing a high-powered CO2 laser was designed and constructed to study ignition characteristics of a series of RDX-based nitramine composite propellants. Interactions between the infrared laser beam and nitramine composite propellants revealed a number of interesting processes. The laser ignition of composite propellants involves many complex thermophysiochemical processes including gasification, initiation of a luminous flame, propagation of the flame, and chemical reactions near the sample surface as well as heat conduction in solid phases. In general, the delay time based upon the onset of light emission decreases monotonically with the increase of incident laser energy flux. Keywords:Ignition, Carbon dioxide laser, Nitramine, Composite propellants, Thermal decomposition, Reaction mechanisms, Ignition delay, Radiation ignition, Crack propagation, Crack branching, Interrupted burning, Depressurization, Extinguishment.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 100
Get Book Here
Book Description
This report presents results of a study of combustion processes in solid propellant cracks. As might be expected, under moderate chamber pressurization rates (10,000 atm/s), the theoretical predictions, as well as the experimental observations, indicate that the ignition front propagates from the entrance of the crack to the tip. However, under rapid chamber pressurization rates (100,000 atm/s or higher), the tip region of the crack was observed to ignite before the arrival of the convective ignition front. (Ignition is defined here as the onset of emission of luminous light from the propellant surface with some material loss. A theoretical model has been developed to explain the tip ignition phenomena. The model considers: a one-dimensional transient heat conduction equation for the solid phase; and one-dimensional, unsteady mass and energy conservation equations for the gas phase near the crack tip. Both experimental and theoretical results indicate that the ignition delay time decreases as the pressurization rate is increased.
Author:
Publisher:
ISBN:
Category : Government reports announcements & index
Languages : en
Pages : 1364
Get Book Here
Book Description
